WO1999052645A1

WO1999052645A1 - Method and installation for spraying coating product

Info

Publication number: WO1999052645A1
Application number: PCT/FR1999/000833
Authority: WO
Inventors: Dominique Cebola; Michel Fouvet; Adrien Lacchia
Original assignee: Sames S.A.
Priority date: 1998-04-15
Filing date: 1999-04-09
Publication date: 1999-10-21
Also published as: FR2777483A1; AU3152199A

Abstract

The invention concerns a method for spraying coating products on objects (10, 10') continuously moving past in forward motion direction (XX'), said method consisting in spraying said product on the sides of said objects by means of sprayers arranged on the sides of said forward motion direction, each sprayer being dedicated to coating each object lateral zone. The invention is characterised in that it consists in exchanging, when passing from one object (10) to the next (10'), two coating zones (I, II) assigned to two adjacent sprayers or group of sprayers. The installation is provided with lateral machines including two arms each supporting at least one sprayer in a rising motion and in a movement following the objects along the forward motion direction.

Description

METHOD AND INSTALLATION FOR SPRAYING COATING PRODUCTS

The invention relates to a method and an installation for spraying coating product onto objects in the process of scrolling.

In the automotive industry in particular, it is known to make a coating product spraying station on vehicle bodies by means of a so-called "roof" machine, the projectors of which are dedicated to coating generally horizontal surfaces. of the bodywork such as the hood, the roof or the trunk, and of so-called "lateral" machines, dedicated to coating the sides of the bodywork. A known coating station, for example from EP-A-0 618 013, comprises a roof machine and three lateral machines arranged on each side of the conveyor line. The total size of such an installation in a direction parallel to the conveyor line is important, since the succession of lateral machines occupies a cabin length which cannot be reduced. Indeed, - it is advisable to provide a side access to each of the lateral machines and the distance between the sprayers of two adjacent lateral machines cannot be reduced without the risk of seeing a part of the coating product coming from a projector being deposited on a nearby projector.

In addition, the spacing of the lateral machines must be large enough to allow the cleaning and priming operations of each headlamp with a coating product adapted to the color chosen for each new bodywork arriving opposite each of the lateral machines. Indeed, the time allocated to the change of coating product corresponds to the interval during which no bodywork is facing the headlamp.

However, the current methods of production of motor vehicles are adapted to the choices of the customers, in particular as regards the color of the body of the vehicle. As a result, the bodies that run on a production line in variable colors and that it is very often 2 necessary to change the coating product projected in an installation between two successive bodies.

Taking into account the running speeds of the current conveyors, which are of the order of 4 to 7 m / min, and the distance separating two bodies on such a conveyor, which is of the order of a meter, the changeover time from tint allocated for each projector is around 12 seconds. The quality of cleaning and priming of new coating product which are necessary in order to avoid any risk of appearance defect on the body cannot always be achieved in such a short time. The current trend is to increase production rates, but this increase is limited because of the times of change of coating product. Furthermore, it is known from patent application WO-95

09 697, a lateral machine for installation for spraying coating product capable of movement following the bodywork, that is to say movement of the headlight or headlights which it carries parallel to the conveying direction. This machine does not, by itself, optimize the time of color change allocated to each projector.

It is to these drawbacks that the invention more particularly intends to remedy by proposing a method and an installation which make it possible to optimize the time of color change allocated to each projector, while retaining economically acceptable speeds of scrolling of the objects. In this spirit, the invention relates to a method of projecting coating product on the objects being continuously scrolled along a direction of advance, this method consisting in projecting the product on the sides of the objects by means of projectors arranged on the sides of the direction of advance, each spotlight being dedicated to coating a lateral zone of each object, characterized in that it consists in swapping, when passing from one object to a next object, two zones covering allocated to two adjacent projectors or groups of projectors.

Thanks to the method of the invention, it is possible to use the differences in length of the zones allocated to each 3 projector or group of projectors to start or end cleaning and priming operations in masked time, that is to say when another projector or group of projectors is already or still in operation, facing an object being scrolled.

According to a first advantageous aspect of the invention, the method consists in dividing at least one coating zone into several elementary zones successively coated, at least one projector being moved, during projection, facing at least one elementary zone, in a movement of altitude and tracking parallel to the direction of advance. This division of a coating zone into several elementary zones makes it possible to adapt the projection parameters, such as the flow rate of coating product, the high voltage possibly used and the flow rate of drive air, while controlling the movement. relative of the projector (s) with respect to each elementary area in an appropriate manner. One can, in particular, provide to move the projector during projection in the object repository generally parallel to a main direction of at least one elementary zone of elongated configuration, such as for example an amount of barrier breeze, side window or quarter window on a motor vehicle body, these amounts being particularly delicate to coat by conventional methods.

According to another advantageous aspect of the invention, the method consists in starting the cleaning and priming operations in new coating product of the spotlight (s) dedicated to the shortest zone parallel to the direction of advance, before cutting of the projector (s) dedicated to the longest zone of the same object parallel to the direction of advance, at the end of the coating of the object.

It is also advantageous to plan to complete the cleaning and priming operations in new coating product of the projector or projectors dedicated to the longest zone of an object parallel to the direction of advance, after the start of the projectors. dedicated to the longest area parallel to the direction of advance of a next object. 4

According to another advantageous aspect of the invention, the method consists in resetting each projector or group of projectors parallel to the direction of advance concomitantly with the cleaning and priming operations of the projector. This aspect of the invention makes it possible to use the tracking stroke of the lateral machine to increase the relative speed of the projector relative to the objects and thus decrease the total duration of activation of the projectors, therefore increasing the duration used for cleaning the spotlights. According to another approach, this aspect of the invention makes it possible, on the contrary, to reduce the relative speed of the projector relative to the object to be coated, in particular for coating complex objects.

The invention also relates to an installation making it possible to implement the method as described above and, more specifically, an installation comprising lateral machines arranged on either side of a conveyor line, each lateral machine supporting at least one moving projector at altitude and in a tracking movement parallel to the direction of advance. This installation is characterized in that each lateral machine comprises two arms each supporting at least one spray of coating product, these arms being driven in displacement by drive means located in a common chassis, these arms being able to move the projectors alternately opposite two lateral zones of the objects in a movement at altitude and in a movement for tracking the objects, along the direction of advance.

According to an advantageous aspect of the invention, the drive means are provided so that the spacing of the arms of the lateral machine is variable during the product spraying phases and during the cleaning and priming phases of the projectors .

The invention also relates to an installation for spraying coating products on motor vehicle bodies in the process of continuous travel in a direction of advance on a conveyor line, this installation comprising a roof machine and at least one machine. 5 lateral disposed on each side of the conveyor line, characterized in that it comprises, on each side of this conveyor line, a common chassis inside which are arranged means for driving two operating arms provided each of at least one spray of coating product facing lateral zones of coating of bodies in an altitude movement and a tracking movement. This installation makes it possible to efficiently coat the sides of motor vehicle bodies with four projectors distributed two by two, on each side of the conveyor line.

The invention will be better understood and other advantages of it will appear more clearly in the light of the following description of a method and an installation for spraying coating product in accordance with its principle, given only to as an example and made with reference to the accompanying drawings in which:

- Figure 1 is a schematic representation of principle in perspective with partial cutaway of an installation for spraying coating product according to one invention;

- Figure 2 is a schematic representation of the principle of a motor vehicle body;

- Figure 3 is a side view of two bodies of motor vehicles being scrolled in the installation of Figure 1.

The installation shown in Figure 1 comprises a cabin 1 whose roof is not shown for clarity of the drawing and whose vertical partitions l define a coating volume along a conveying direction XX 'parallel to the rails 2 of a conveyor. A beam 3 on which three projectors 4 are mounted is supported by two gantries 5 and 6 arranged on either side of the rails 2. The gantries comprise devices for driving the beam in altitude, parallel to the direction XX 'and in a rotational movement around its largest axis, these drive means can be in accordance with the technical teaching of WO-A-95/09 697. The elements 3 to 6 form a machine called "de 6 roof "intended for coating the generally horizontal parts of a motor vehicle body 10 visible in FIG. 2 such as the hood 11, the roof 12, the trunk 13, the front face 14 and the rear face. other body parts

10, that is to say on its sides, are arranged on either side of the conveying direction XX ′ two symmetrical machines 21 called lateral machines. Each lateral machine 21 comprises a chassis 23 inside which are arranged means for driving two arms 24 and 25 each supporting at least one spray of coating product 26, respectively 27. It is possible to access these means drive by doors 28 arranged on the sides of each machine 21 and on its rear face, that is to say its face opposite arms 24 and 25.

The drive means of the arms 24 and 25 are provided to move the latter in a movement in altitude in a vertical direction ZZ ', in a tracking movement parallel to the direction XX' and in a penetrating movement in a direction YY 'orthogonal to directions XX' and ZZ '.

One can also provide that each projector 26 or 27 is mounted on a wrist 24a. or 25a. arms 24 and 25 articulated at the end of these arms about an axis generally parallel to the direction XX '. In view of the above, the projectors 26 and 27 can be moved opposite one side of the body 10.

The operation of the installation of FIG. 1 is explained with reference to FIG. 3. It is assumed that a motor vehicle body 10 is moved at constant speed on the conveyor and arrives opposite the lateral machines 21 after being passed under beam 3 of the roof machine.

As can be seen more particularly from FIG. 2, each side of the body 10 can be divided into two zones respectively I and II, zone I corresponding to the upper part of the side of the body, while zone II corresponds to the part lower of the doors located between the two front wheel arches 15 and rear 16. In the vehicles 7 modern, zone III on the side of the body, which corresponds to the lower part of the wing located in front of the front wheel arch 15, is intended to be covered by an overhanging part of the front bumper of the vehicle. Likewise, zone IV corresponding to the lower rear part of the rear wing of the bodywork 10 is intended to be covered with an overhanging part of the rear bumper of the vehicle. In view of the above, zones III and IV need not necessarily be coated with the coating product obtained from the projectors 26 and 27.

We denote by L _τ the length of zone I and we denote by L _IX the length of zone II. It is expected that one of the projectors, for example the projector 27, is dedicated to the coating of zone I of the body 10, while the other projector, that is to say the projector 26, is dedicated to the coating of zone II. Under these conditions and as is clear from Figures 2 and 3, the headlamp 27 works over a length L _x substantially greater than the length h _ιτ on which the headlamp works 26. Referring to Figure 3 and the first bodywork

10, the headlamp 27 is activated to project coating product when a point P _τ located at the front of the zone I reaches opposite the headlamp 27 due to the continuous movement of the bodies on the conveyor. The projection is cut off when a point Q _τ passes in front of the projector 27. The projector 26 is activated when a point P _τι arrives opposite the projector 26 while its operation is interrupted when a point Q _τι arrives opposite the projector 26. In accordance with the method of the invention, the zones I and II are alternately allocated to the projectors 26 and 27. Thus, in FIG. 3, the projector 26 is activated when a point P ' _τ comes opposite of the projector 26 and cut off when a point Q ' _τ exceeds it, while the projector 27 is activated when a point P' _XI reaches its level while its operation is interrupted when a point Q ' _τι exceeds it.

In view of the above, the time during which the projector 27 is not active corresponds to the interval of 8 times separating the passage through the headlamp 27 from point Q _τ for the body 10 and that from point P ' _X1 for the body 10', which is represented by the time interval Δ ₂₇ in FIG. 3. L ' interval Δ ₂₇ is equal to the distance separating the points Q _τ and P ' _ιτ divided by the conveying speed. In the same way, the time during which the headlight 26 is not activated corresponds to the time interval separating the passage in front of the headlight 26 of the points Q ' _IX of the body 10 and P' _τ of the body 10 ', which is represented by the interval Δ ₂₆ in FIG. 3, this time interval Δ ₂₆ being equal to the distance separating the points Q _1X and P'j- divided by the conveying speed.

It is understood that the intervals Δ ₂₆ and Δ ₂₇ are greater than the interval Δ ₀ between the passage of the rear end of a bodywork and the passage of the front end of a following bodywork on the conveyor line. The fact that the intervals Δ ₂₆ and Δ ₂₇ are greater than the interval Δ ₀ makes it possible to further increase the time allocated to the cleaning and priming operations in coating product of each projector 26 and 27.

After coating the bodywork 10 ', zone I is again allocated to the headlight 27 while zone II is again allocated to the headlight 26, which corresponds to the operating mode used for coating the bodywork 10. In these conditions, it is possible to consider installing the bodies on the conveyor with a higher density, that is to say reducing the difference L ₀ between two successive bodies, that is to say the interval of time Δ ₀ , without reducing in the same proportions the time intervals Δ ₂₆ and Δ ₂₇ which retain a minimum duration resulting from the difference in the lengths L -, - and L _π .

It is also possible to consider keeping the distance L ₀ between two vehicles and increasing the speed of the conveyor 2, which also has the effect of reducing the intervals Δ ₀ , Δ ₂₅ and Δ ₂₇ . This can be envisaged, since the intervals Δ ₂₆ and Δ ₂₇ are much greater than the interval Δ ₀ .

The coating zone II is relatively simple in shape, so that the arm which supports the projector is animated by a 9 essentially vertical and oscillating movement, while the zone II is moved opposite the projector. On the other hand, zone I is relatively complex in shape and includes parts such as the windscreen, side window and quarter panel uprights which are known to be difficult to coat.

The coating zone I is divided into several elementary zones A, B, C, D, E, F and G which appear in FIG. 3 as as many zones of relatively simple geometry, each of these zones being able to be coated successively with the same headlamp during the advance of the bodywork opposite this headlamp. To do this, it is essential that the designer is capable of tracking movements of the body, that is to say movements parallel to the axis XX 'so as to allow relative movements relative to the body parallel to its greatest axis.

Returning to the covering of the bodywork 10 in FIG. 3, the part A is first coated while the headlamp is driven by a movement of vertical oscillations, then the headlamp is raised to the level of the vehicle roof and lowered forward parallel to the main direction BB 'of zone B in the frame of reference of the bodywork which moves at constant speed relative to the chassis 23 of the machine 21. This can be obtained by adequate programming of the means d 'driving the arm 25 in the directions XX' and ZZ 'taking into account the speed of advance of the bodywork 10 on the conveyor 2. It is then possible to proceed with the coating of the elementary zone C by oscillating movements essentially vertical of the headlight 27, then bring the headlight 27 up to the level of the vehicle roof to give it a generally vertical downward movement in the frame of reference of the body 1 0 during movement to cover the area D which has a main direction DD 'generally vertical, since it corresponds to the door jambs. In the same way, the quarter pillar F is coated by giving the projector 27 a movement parallel to the main direction FF 'of the zone F which is inclined in the reference frame of the 10 body 10 during movement.

As the projectors 26 and 27 alternately paint the zones I of the bodies which follow one another on the conveyor line, each arm 24 and 25 of the lateral machine 21 must be capable of movements at altitude and of follow-up movement.

The fact of using a common chassis for the machine 21 makes it possible to obtain great compactness in the direction XX ', therefore to reduce the overall cost price of the cabin 1, in particular due to the reduction in the lengths of partitions, ventilation or conveyor systems.

With reference to FIG. 3 and taking into account the fact that the interval Δ ₂₆ begins before the start of the interval Δ ₂₇ , it is understood that it is possible to start the cleaning and priming operations of the projector 26 before the end of the projection phase by means of the projector 27 on the elementary zones D to G of the bodywork 10. To do this, the projector 26 is directed vertically downwards by rotation of the wrist 24a_ in the direction of a grating or a purge system provided for this purpose, which avoids any danger of accidental projection on the body 10 during scrolling. In the same way, the cleaning and priming operations of the headlamp 27 in new coating product can be extended beyond the passage of the point P ' _{τ in} front of the headlamp 26 for the bodywork 10', so that the cleaning of the headlamp 27 and its ignition take place while the headlamp 26 has already started coating the elementary zone A, or even zones B and C, of the bodywork 10.

The projectors 26 and 27 are also moved parallel to the axis XX ′ during the cleaning and priming operations, to readjust them optimally parallel to this direction in order to reduce the total duration of the coating by increasing the relative speed of the headlight relative to the bodywork in the course of running parallel to the direction XX 'or on the contrary by reducing this speed, in particular for complex bodywork.

The movement of the arms 24 and 25 parallel to the axis YY 'makes it possible to compensate for the bulging nature of the sides of a vehicle 11, the width of which is greater at the level of a central part than at the level of the roof or of the rocker panels.

The drive means of the arms 24 and 25 are provided so that these arms are movable independently of one another parallel to the direction XX ', these arms being able to be approached or distant from each other during the projection or cleaning / priming phases. This allows rapid cleaning / priming operations and avoids soiling of a projector by the cloud of product from a neighboring projector. The adjustable nature of this spacing also allows the recalibration of each projector between two projection phases while the other projector is still or already activated, that is to say during projection.

In the foregoing description, only the operation of the lateral machine 21 situated on the left of FIG. 1, with respect to the direction of advance XX ′, has been described. The operation of the second lateral machine 21 is similar.

The invention has been shown with arms 24 or 25 each supporting a single projector. It is however possible that each arm supports a group of several projectors.

Claims

12 CLAIMS

1. A method of projecting coating product onto objects (10, 10 ') during continuous scrolling along a direction of advance (XX'), said method consisting in projecting said product onto the sides of said objects at means of projectors (26, 27) arranged on the sides of said direction of advance, each projector being dedicated to coating a lateral zone of each object, characterized in that it consists in swapping, during the passage of a object (10) to a next object (10 '), two covering zones (I, II) allocated to two projectors (26, 27) or groups of adjacent projectors.

2. Method according to claim 1, characterized in that it consists in dividing at least one coating zone (I) into several elementary zones (AG) successively coated, at least one projector (26, 27) being moved, in progress projection, facing at least one elementary area, in an altitude movement (ZZ ') and tracking parallel to said direction of advance (XX').

3. Method according to claim 2, characterized in that it consists in moving said projector (26, 27), during projection, in the reference frame of said object, generally parallel to a main direction (BB ', DD', FF ') of at least one elementary zone (B, D, F) of elongated configuration.

4. Method according to one of the preceding claims, characterized in that it consists in starting the cleaning and priming operations in new coating product of the projector (s) (26) dedicated to the shortest area (II) parallel to said direction of advance (XX ′), before switching off the projector (s) (27) dedicated to the longest zone (I) of the same object (10) parallel to said direction of advance, at the end of the coating of said object.

5. Method according to one of the preceding claims, characterized in that it consists in terminating the cleaning and priming operations in new coating product of the projector (s) (27) dedicated to the longest area (I) an object (10) parallel to said direction of advance (XX '), 13 after the start of the projector (s) (26) dedicated to the longest area (I) parallel to said direction of advance of a next object (10 ').

6. Method according to one of claims 4 or 5, characterized in that it consists in resetting each projector (26, 27) or group of projectors parallel to said direction of advance (XX ') concomitantly with the operations of cleaning and priming said projector.

7. Installation for spraying coating product onto objects (10, 10 ′) during continuous scrolling in a direction of advance (XX ′) on a conveyor line (2), said installation comprising lateral machines (21 , 22) arranged on either side of said conveyor line, each lateral machine supporting at least one projector (26, 27) movable at altitude (ZZ ′) and in a tracking movement parallel to said direction of advance, characterized in that each lateral machine comprises two arms (24, 25) each supporting at least one spray of coating product, said arms being driven in displacement by drive means located in a common frame (23), said arms being able to move said projectors alternately opposite two lateral zones (I, II) of said objects in a movement in altitude and in a tracking movement of said objects, along said direction of advance (XX ').

8. Installation according to claim 7, characterized in that said drive means are provided so that the spacing of said arms of said lateral machine is variable during the product spraying phases and during the cleaning and lighting of the projectors.

9. Installation for spraying coating product onto motor vehicle bodies (10, 10 ′) during continuous scrolling in a direction of advance (XX ′) on a conveyor line (2), said installation comprising a machine roof (3-6) and at least one lateral machine (21, 22) disposed on each side of said conveyor line, characterized in that it comprises, on each side of said conveyor line, a common frame (23 ) inside which are arranged means for driving two arms (24, 25) of 14 maneuvers each provided with at least one projector (26, 27) of coating product facing lateral zones (I, II) of coating of said bodies in a movement at altitude (ZZ ') and a tracking movement (XX' ).